In a conference call with major league sports commissioners on Saturday, President Donald Trump said he believes the NFL season should start on time in September, sources familiar with the call told ESPN.

Trump also said he hopes to have fans back in stadiums and arenas by August and September, sources said, although it is currently unclear if medical experts find that to be a realistic timeline amid the current coronavirus pandemic.

"I want fans back in the arenas," Trump said later in a briefing at the White House. "I think it's ... whenever we're ready. As soon as we can, obviously. And the fans want to be back, too. They want to see basketball and baseball and football and hockey. They want to see their sports. They want to go out onto the golf courses and breathe nice, clean, beautiful fresh air."

Trump declined to give an exact date when reporters asked when he anticipates fans returning to arenas, saying, "No, I can't tell you a date, but I think it's going to be sooner rather than later."

He also said he told the commissioners that he recognizes "the good work being done by many teams and players" to care for their communities and fan bases dealing with the outbreak.

California Governor Gavin Newsom addressed whether he believed that the NFL season would open in August or September with 80,000 fans, telling reporters Saturday, "I'm not anticipating that happening in this state."

"It's interesting, I have a lot of friends that work in Major League Baseball and in the NFL, they've been asking me -- in fact, a well-known athlete just asked me, a football player, if he expects to come back. I said, 'I would move very cautiously in that expectation,'" Newsom said.

"So look, I'm not here to second-guess anybody, but I am here to say this, our decision on that basis, at least here in the state of California, will be determined by the facts, will be determined by the health experts, will be determined by our capacity to meet this moment, bend the curve and have the appropriate community surveillance and testing to confidently determine whether that's appropriate. And right now I'm just focused on the immediate, but that's not something I anticipate happening in the next few months."

NBA commissioner Adam Silver told those on the call with Trump that the leagues were the first to shut down and that they would love to lead the way in restarting the economy once there is an "all clear" from public health officials, sources familiar with the call told ESPN.

The NBA was the first league to suspend play, on March 11.

On the call, Trump raised the idea of the leagues working together to lobby for tax incentives that used to exist for entertainment expenses, such as the ability to deduct concessions and tickets from taxes, sources said. That would be a way for leagues to jump-start fans' ability to return to stadiums in a difficult economy.

The call included major sports commissioners and top executives from the NFL, NBA, Major League Baseball, NHL, Major League Soccer, WNBA, WWE, the PGA Tour, LPGA, UFC, NASCAR, IndyCar and Breeders' Cup, according to a White House pool report.

Trump also took to Twitter on Saturday to reassure Little League baseball players that their season will resume soon.

The Associated Press contributed to this report.